3D Ising Superconductivity in As-Grown Sn Intercalated TaSe<sub>2</sub> Crystal.

Zheng, Bo; Zhang, Xiaoming; Wang, Kaipu; Li, Ruimin; Cao, Jin; Wang, Changlong; Tan, Haige; Li, Zhidong et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

2D Ising superconductivity emerges in noncentrosymmetric 2D materials, differing from conventional 2D/3D superconductivity. Here, we report the synthesis of a new polymorph of intercalated layered materials, where two layers of Sn are intercalated in between every two layers of TaSe<sub>2</sub> (2Sn-2TaSe<sub>2</sub>), in contrast to the commonly observed single-layer intercalation. Remarkably, the as-grown 2Sn-2TaSe<sub>2</sub> single crystals possess a high quality of crystallinity and showcase 3D Ising superconductivity. Transport measurements and theoretical calculations show that the 2Sn-2TaSe<sub>2</sub> having C<sub><i>3v</i></sub> point group symmetry induces formation of Ising pairs, which intriguingly exhibits, on one hand, an in-plane upper critical field surpassing the Pauli limit by a factor of 2.6 like a 2D Ising superconductor but, on the other hand, a temperature- and field-dependent conductivity characteristic of conventional 3D superconductivity. Our findings demonstrate the persistent 2D Ising pairing in 3D, paving the way for exploring dimensional physical behaviors by intercalating layered materials.